在RichTextBox C#中突出显示整行

private void richTextBox_TextChanged(object sender, EventArgs e)
{
    HighlightCurrentLine();
}

private void HighlightCurrentLine()
{
    int lineIndex = richTextBox.GetLineFromCharIndex(richTextBox.SelectionStart);
    int lineStart = richTextBox.GetFirstCharIndexFromLine(lineIndex);
    int lineEnd = richTextBox.GetFirstCharIndexFromLine(lineIndex + 1);

    richTextBox.SelectionStart = lineStart;
    richTextBox.SelectionLength = lineEnd - lineStart;
    richTextBox.SelectionBackColor = Color.Yellow;
}

private void Form_Load(object sender, EventArgs e)
{
    richTextBox.TextChanged += richTextBox_TextChanged;
}